Automotive brake system



' g- 1932- c. A. CAMPBEL L 1,371,110

AUTOMOTIVE BRAKE SYSTEM Original Fil ed Aug. 8, 1928 Zhwcntor' Gttomcgs Patented Aug. 9, 1932 U ITED sTArssf cnnnnns A.

' PATENT orn-" 105 OAMIEBELL, OF WATERTOWN, NEW YORK, ASSIGNOR 1'0 NEW AIR BRAKE COMP ANY, A CORPORATION OF NEW JERSEY nucrouorwn BRAKE s stem or ginal application filed August 8,1928, Serial 1%. 298,229, and i Canada Ja al-v 1c, 1922. Divided 7 and this application filed Qctober 9, 1980. Serial No. 487,615.

" This invention relates to fluid pressure brake systems, and-will be described as applied to a so-called vacuum system in which the necessary suction is derived by connect- 5 ing the brake system to the intake manifold ;0 In automatic brake systems two lines of of an internal combustion engine. The present application is adivision of myzrior applicationSerial; No.'298,'229, filed ugust 8, 1928. P

development have been followed; the'first, and commercially the more common type is known as the Servo-motor type, and is arranged so that when the opef'at'or depresses the ordinary foot pedal the brake motor assists him." The other type, commonly called the straight power type, makes'use of a brake valve entirely distinct from the'brake'pedal,

and produces a graduated power application of the brakes without depression of the ordi nary foot, pedal.

The present application is directed to the construction and mounting of the brake cylinder in such a way that it may beinterposed in conventional brake rigging without impairing the normal foot operation of the brake. pedal. The brake is-of -the'straight power type. 1. I

Generally, stated, I make use of a suction cylinder which in release position is subject to atmospheric pressure at both ends. This cylinder is sustained by av pairof links one connected to the cylinder and the other to the piston rod, the two links being interposed between sections of one of the pull rods formmg part of the brake rig'ging. Y

So arranged the device is applicable to,

" brakes of themechanical type, regardless of pendingdinks with' a series of holes which he attainment of difierent brake lever the number of wheels e'quipped with brakes and it becomes possible to provide the suspermit ratios for the. cylinder without disturbing the foot brake lever ratio.' In this way a single size of cylinder-"is rendered applicable to motor cars of various weights and adjust-' ment is provided for different adhesions such i i-are incident to snow in winter and .the 1e'.., i l Inits release position the piston is at its means of the usual cam mechanism shown)- which is actuated by the lever 22. When the lever 22 swings in the counter The foot lever customarily the lever 22 is indicated at 23.

it-will be understood that trolled by other mechanisms.

1 The preferred embodiment of the invention is illustrated in the accompanying drawling, which is a diagrammatic view, partly in section,'showingthe brake cylinder and v Wale? subject matter of the parent application, but it may be con- 1 brake pedaLcontrolling valve, and so much of a motor vehicle as is necessary to explain; the construction andfioperation of the device.

y In the drawing, 11 indicates the intake manifold of an internal combustion engine, for example, the gordinary gasoline engine used on motor vehicles. 12 is a carbureter and 13 is the throttle lever. This lever operj ates an ordinary butterfly valve, and in idling 16. A. portion ofthe floor or frame work.

of an ordinary motorvehicleisconventionally represented at 17, and 18 is the inclined footboard. 19 represents a brake drum and '21 a brake band poacting therewith and ca- I pable of being contracted upon the drum by (not clockwise direction the brakes are applied. used to operate The parts so far described are merely representativeof'similar parts, common tmpractically all, automobiles, and will take various forms according to the preference of designersi In the conventional brake the levers 23 and 22 are connected by a tension link or by a plurality of tension links connected to mounted on the framemember 17 and carry 'the swinging brake cylinder levers 26 and 27. The lever26 is connected by link 28 with the foot lever 23 and the lever 27 is connected by two links 29 and 31 with the lever .22. The links 29 and 31 are pinned to each other at 32 and are there guided by a. swinging link 33. A tension spring 34 operates to release the brakes.

' Below the points of connection of the links 28 and 29, the levers 26 and 27 areeach provided witha series of spaced holes 35 to give variable points of attachment forthe' brake cylinder. This cylinder is made up of two heads 36 and 37, a barrel portion 38 and a plurality of tie-rods 39 with nuts 41.

The tie-rods clamp the heads-in sealing relation with the opposite ends of the barrel.

The head 36 carries at its centera boss 42 which is pivoted to the brake cylinder lever 26. The head 37 has a central aperture with a stufiing box 43 and through this works the tubular piston rod 44 connected to a brake piston 45. The head 37 is provided with an atmospheric port and dust strainer 2 indicated generally by the numeral 40. The brake piston 45 works in the cylinder barrel 38 in which it is sealed by. means of a cupleather 46. The cup-leather 46 is clamped in-place by means of a follower 47.

The guide rod 48 fixed in the head 36 slides through the bushing 49 and extends into the tubular piston rod 44. In this way the piston is guided independently of the barrel 38 and alinement is maintained at all times, notwithstanding the fact that'the cylinder is supported at its rear end by the rod 44, which, as shown, is pivoted to the lower end of the lever/ 27. In release position the piston 45 is against the head 37 and in such case the brakes may be applied by depressing the foot lever 23 in the usual manner. Power application of the brakes is made by evacuating the space to the left of the piston 45. The effect is to draw the levers 26 and 27 toward each other. Since the lever 23 is arrested by the usual limit stop 51 the lever 22 is necessarily swung to the left to apply the brakes.

The brake valve is indicated generally by the numeral 52 applied to its body. It has a suction connection 53 with the intake manifold 11. p The connection to the brake cylinder is made up of a pipe 54 and a flexible hose 55 connected thereto and to a suctiomnipple 56 in the head 36 of the brake cylinder.

The construction of the brake valve 52 is not material to the present invention beyond pointing out that the accelerator push rod 86 which terminates at its upper end in the accelerator button 87. is slidable through the actuating member of the brakevalve, and that this actuating member applies the brakes when the push rod 86 moves upward. The push rod-86 is formed with a shoulder,not,. shown, which engages the controlling member-of the brake valve and forces this upward to apply the brakes if the plunger 86 be moved upward beyond the normal idling position.

\celerator push rod 86 upward or outward in a brake applying direction. The other arm of the bell crank 93 is connected to a push rod 95. This carries an adjustable thrust member 96 threaded thereon and locked in place by a check nut 97. The thrust member 96 telescopes into and enters into a one-' way thrust engagement with a sleevemember 98 pivoted to the lever 13.

The parts are preferably so adjusted that when the shoulder on the push rod 86 picks up the actuating member of the valve 52 to shift the same in a brake-applying direction, the thrust member 96 will have movedslightly out of thrust relation with the sleeve 98. This is to allow a little lost motion or interval between the position at which the throttle commences to open when push rod 86 is depressed, and the position at which the brake commences to apply when the push rod is allowed to move upward from idling position.

The accelerator button 87 thus serves as a dual control having an intermediate neutral position in which the engine idles, and the brakes are .released. If depressed from this position the brake is held released and, the motor is accelerated. If allowed to rise above this position, under the urge of the spring 94, the throttle is left in idling position and the brakes .are applied with progressively increasing force, according to the distance the button 87 is allowed to rise. The efi'ect of the brake valve is to evacuate thespace forward, i. e., to the left of the piston 47, drawing the levers 26 and 27 to gether and shortening the connection between=the foot pedal 23 and the rock lever 22. In release position both sides of piston 47 are subject to atmospheric pressure and the piston moves to the position shown in the drawing, in, which the brakes are released. In release position the brake cylinder acts merely as a connecting link between the levers 26 and 27 and the brakes may be applied by depressing the foot pedal 23 as usual.

I The provision of the holes 35 in the levers 26, 27,- permits changes in the leverage of the brake cylinder with respect to the brake rig- I ging without affecting the leverageof the. brake pedal 23 relatively to the rock lever 22. For best braking efl'ect, it is important loo 15 between it and the throttle are claimed inthe to apply the brakes with a force-nearlyv but not quite suflicient to cause sliding of the wheels; The adjustment of the brake cylinder relatively to the levers 26 and .27 will 5 allow a single brake cylinder to be adjusted.

to conform to the requirements of cars of different weights or to different tractive conditions. For example, on snow it might-be desirable to use a lower lever ratio and thus reduce the tendency to skid. A heavier lcver ratio can be used on heavy cars. Also the preferences of the operator will control to a considerable degree. t

The valve mechanism, and the connections parent I What is claimed is,

.11 a rake mechanism, the combination application above identified."

of an operator. actuated member; abrake; a'

pair of normally substantially parallel swinging levers, one-connected with said operator actuated member and the other connected with said brake; abrake applying -motorcompris'ing a cylinder and piston, said 2 motor when in its inert condition serving as a mechanical connection between said levers; and means for operat ng sald motor by pressure fluid without requiring motion of said operator actuated member.

2.. Ina brake mechanism, the combination of an operator actuated member; abrake; a

pair of normally substantially parallel pivoted levers; said levers extending in the same direction fromtheir' pivots, and one being connected with the operator actuated member and the other-with the brakepa brake applying motor comprisinga cylinder and piston, said motor in its inert condition servingas a mechanical connection Between the 4" levers; means for adjusting the points; of

connection of said motor with both the levers whereby the leverage relation of the motor. to the brake may be varied without varying the leverage relation of the operator actuated' member, to the brake; and means for operating saidmotor by fluid pressure. 3. In-a combined power and manually operable brake mechanism, thecombination of a brake; .an operator actuated member; a

- brake.valve'; a pair of pivoted levers, one

connected with said 0 erator'actuated memher and the, other with said brake; and a a pressure motor subject to control by said valve and comprising. a cylinder connected to one lever and a piston connected to the a connected with said member and the other I with said brake; a pressure motor including a piston, a cylinder, and means for limiting the relative motion thereof, said motor be ing subject'to control by said brake valve;-

pivoted connections between the piston and one of said levers and between the cylinder and the other of said levers; and means for adjusting said pivoted connections to vary the effective lengths ofsaid levers.

' 5. In a combined power and manually operable brake mechanism, the combination of a brake; an op'erator actuated member; a

brake valve; a pair of pivoted levers, one connected with said member and the other with said brake; a cylinder connected to. one

of said levers; a piston connected to the other of said levers; a piston guide wholly within.

piston guide aline'd with said guideway; a

piston working in said cylinder guided. by

said guideand having a hollow piston rod which receives said guide and reciprocates in said guideway; a pair of movable members adapted for connection with brake rigging; and connections between said cylinder and one of said members and betweensaid piston rod and the other of said members,

said connections serving to support saidcylinder and piston.

Y 7 In a brake mechanism, the combination of a pair of supports; a pair of levers pivoted to said supports; brake rods connected with said levers; -and' a brake motor comprising a cylinder connected to one of said levers and apiston connected to the otherof said levers, said piston and cylinderserv ing when the motor is-inert as a mechanical connection between said levers, and at such" time serving to maintain said levers substantially parallel with each other, and said motor when active serving to displace said leivers from such parallel relation.

-In testimony whereof I have, signed my name to this specification. CHARLES A. CAMPBELL.

other lever, said motor being supported by said levers and serving, when in-its inert condltion, as a pos1t1ve mechanical connection between said levers when the operator actuated member ismoved in abrake applyl a-pairl' of pivoted levers, one

ing direction.

4. In a combined power and manually ope'rable brake mechanism, the combinationof a brake; an operator actuated member; a 

